Proton-linked monocarboxylate transporters (MCTs) are a family of highly homologous trans-membrane symporters, involved in the transportation of monocarboxylic acids across the plasma membrane such as: lactate, pyruvate, branched-chain oxoacids derived from leucine, valine, and isoleucine, ketone bodies, acetoacetate, β-hydroxybutyrate and acetate. Thus, MCTs play an important role in metabolic communication among cells and in mammalian metabolism.